[PATCH 1/6] drm: bridge: samsung-dsim: Support multi-lane calculations

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



If there is more than one lane, the HFP, HBP, and HSA is calculated in
bytes/pixel, then they are divided amongst the different lanes with some
additional overhead. This is necessary to achieve higher resolutions while
keeping the pixel clocks lower as the number of lanes increase.

Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 40 +++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index e0a402a85787..1ccbad4ea577 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -215,6 +215,7 @@
 #define DSI_RX_FIFO_SIZE		256
 #define DSI_XFER_TIMEOUT_MS		100
 #define DSI_RX_FIFO_EMPTY		0x30800002
+#define DSI_HSYNC_PKT_OVERHEAD	6
 
 #define OLD_SCLK_MIPI_CLK_NAME		"pll_clk"
 
@@ -879,13 +880,40 @@ static void samsung_dsim_set_display_mode(struct samsung_dsim *dsi)
 			| DSIM_MAIN_VBP(m->vtotal - m->vsync_end);
 		samsung_dsim_write(dsi, DSIM_MVPORCH_REG, reg);
 
-		reg = DSIM_MAIN_HFP(m->hsync_start - m->hdisplay)
-			| DSIM_MAIN_HBP(m->htotal - m->hsync_end);
-		samsung_dsim_write(dsi, DSIM_MHPORCH_REG, reg);
+		/*
+		 * If there is more than one lane, the HFP, HBP, and HSA
+		 * is calculated in bytes/pixel, then they are divided
+		 * amongst the different lanes with some additional
+		 * overhead correction
+		 */
+		if (dsi->lanes > 1) {
+			u32 hfp, hbp, hsa;
+			int bpp = mipi_dsi_pixel_format_to_bpp(dsi->format) / 8;
+
+			hfp = ((m->hsync_start - m->hdisplay) * bpp) / dsi->lanes;
+			hfp -= (hfp > DSI_HSYNC_PKT_OVERHEAD) ? DSI_HSYNC_PKT_OVERHEAD : 0;
+
+			hbp = ((m->htotal - m->hsync_end) * bpp) / dsi->lanes;
+			hbp -= (hbp > DSI_HSYNC_PKT_OVERHEAD) ? DSI_HSYNC_PKT_OVERHEAD : 0;
 
-		reg = DSIM_MAIN_VSA(m->vsync_end - m->vsync_start)
-			| DSIM_MAIN_HSA(m->hsync_end - m->hsync_start);
-		samsung_dsim_write(dsi, DSIM_MSYNC_REG, reg);
+			hsa = ((m->hsync_end - m->hsync_start) * bpp) / dsi->lanes;
+			hsa -= (hsa > DSI_HSYNC_PKT_OVERHEAD) ? DSI_HSYNC_PKT_OVERHEAD : 0;
+
+			reg = DSIM_MAIN_HFP(hfp) | DSIM_MAIN_HBP(hbp);
+			samsung_dsim_write(dsi, DSIM_MHPORCH_REG, reg);
+
+			reg = DSIM_MAIN_VSA(m->vsync_end - m->vsync_start)
+				| DSIM_MAIN_HSA(hsa);
+			samsung_dsim_write(dsi, DSIM_MSYNC_REG, reg);
+		} else {
+			reg = DSIM_MAIN_HFP(m->hsync_start - m->hdisplay)
+				| DSIM_MAIN_HBP(m->htotal - m->hsync_end);
+			samsung_dsim_write(dsi, DSIM_MHPORCH_REG, reg);
+
+			reg = DSIM_MAIN_VSA(m->vsync_end - m->vsync_start)
+				| DSIM_MAIN_HSA(m->hsync_end - m->hsync_start);
+			samsung_dsim_write(dsi, DSIM_MSYNC_REG, reg);
+		}
 	}
 	reg =  DSIM_MAIN_HRESOL(m->hdisplay, num_bits_resol) |
 		DSIM_MAIN_VRESOL(m->vdisplay, num_bits_resol);
-- 
2.39.2




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux